Log session

Log Session

Capture the why and the what-next of a working session — the context that git history alone never records. A commit says what changed; a session log says what you were trying to do, what you decided, and where to resume.

Deliberately cheap (sonnet/medium): this is structured summarization, not judgment. It must never reach for an expensive model.

Turn contract — verify before ending the turn

✓ The entry was APPENDED to docs/LOGS.md (file edited, not just drafted) with accurate git facts
✓ No past entry was edited
✓ Artifact language: explicit user instruction > the project's declared docs language > English. The CONVERSATION language never decides — a Spanish prompt still produces English PRs/issues/commits/SPECs unless one of the first two says otherwise
✓ The closing `→ Next:` block is printed as the ABSOLUTE last output

About to end the turn with any box unchecked? The turn is NOT done — complete the missing box first (weak models drop end-of-document duties; this list is first on purpose).

When to use

• Before /clear (or your agent's context-reset equivalent) — you're about to wipe context; capture it first.
• Before closing your agent for the day.
• At a natural stopping point — a feature paused mid-way, a thread you want to be able to resume cold.
• After a long session with several decisions worth remembering.

This is the manual, rich counterpart to the lightweight auto-logging hooks the template/ ships (see template/.claude/). The hooks capture the mechanical facts for free on every exit; this skill writes the thoughtful entry when you want one.

Step 0 — Discover the project (always first)

Per the agent guide's Workflow conventions + documentation map, locate the session log. Default path: docs/LOGS.md. If the documentation map names a different location, use that. If no log file exists yet, create it from the shape in template/docs/LOGS.md (a short header + the entry format below) and say so.

If a session-start marker exists (.claude/.session-*.start, written by the template's SessionStart hook), read it to bound the session precisely — it holds the HEAD sha and start time at session open.

Process

1. Establish the session boundary.

   • If a marker is present, the session spans marker_sha..HEAD plus any uncommitted work.
   • Otherwise, use your own conversation context as the source of truth for what happened this session, and corroborate with git log of the recent commits and git status / git diff --stat for uncommitted changes.

2. Gather the mechanical facts (cheaply, with git):

   • branch (git branch --show-current),
   • commits this session (git log --oneline <since>..HEAD),
   • files touched (git diff --stat <since>..HEAD + uncommitted).

3. Write the narrative — the part only you can add:

   • Summary: 1–3 sentences on what this session set out to do and what actually got done.
   • Decisions: the non-obvious choices made and why (the rationale that would otherwise be lost). Link related docs/issues.
   • Next: the concrete next step(s) — the command to run, the unfinished thread, the open question. Write it so a cold reader knows exactly where to resume.

4. Append the entry to docs/LOGS.md, newest at the bottom (append-only, chronological). Use this format so the auto-hook entries and these stay compatible:

   ## <ISO-8601 timestamp> — <branch> — manual
   - **Commits:** <n> (`<short-sha>…<short-sha>`)
   - **Files:** <comma-separated paths, or a count if many>
   - **Summary:** <what this session did>
   - **Decisions:** <key choices + why; omit the line if none>
   - **Next:** <the concrete next step>
   

   If the user passed a note as an argument, prepend it to the Summary.

5. Commit policy. docs/LOGS.md is documentation — keep it coherent, but do not open a PR just for a log entry. If you're mid-feature on a branch, the entry rides along with the next commit. If the working tree is otherwise clean and the user wants it persisted, ask before committing a standalone docs(log): session <date> commit. Never push without the project's push convention.

Guardrails

• Never use an expensive model for this. It's summarization; sonnet is the ceiling, and the hooks do the free mechanical version.
• Don't invent facts. Decisions and next steps come from the actual session (your context + git), not plausible-sounding filler. If a section has nothing real, omit its line rather than padding.
• Append, never rewrite. Past entries are a historical record — don't edit or "tidy" them. Same reasoning as not rewriting a delivered feature's planning artifacts.
• One file, append-only. Don't fan session logs across files.

Portability (agents other than Claude Code)

The workflow is the contract; Claude Code features are conveniences. On an agent that lacks one, apply the fallback — never skip the step the feature enables:

• No Claude Code hooks — the template's auto-logging hooks (SessionStart marker, SessionEnd entry) don't run on other agents, so there is no marker file and no free mechanical entry: this skill is the only journal writer. Run it before ending every session, and bound the session with git alone (Process step 1's no-marker path).
• No /clear — read it as your agent's context-reset / new-conversation equivalent, in the triggers and in the closing block alike.
• No per-skill model:/effort: — the intent stands: use a cheap model for this. It's summarization, never judgment.

Relationship to other skills

• Complements the template/'s SessionEnd hook (free, mechanical, automatic on /clear and exit) and the opt-in SessionStart restore hook (re-injects the last entry to resume context). This skill is the rich, manual entry.
• Pairs with execute-phase's per-feature progress.md: that tracks progress within a feature; the session log is cross-cutting — whatever you touched this session, across features/fixes.
• Not part of the PR gate — it's a working-memory aid, not a merge artifact.

Done when

• A new entry is appended to docs/LOGS.md with at least Summary and Next.

• The mechanical facts (branch, commits, files) are accurate to git.

• The closing → Next: block is printed:

  → Next: /clear (or your agent's context reset) is now safe — the session is captured
    · resume later → the command named in the entry's **Next** line